In the production of oil from underground oil-bearing formations, it is known that primary recovery methods remove only a small portion of the in-place oil. Secondary oil recovery methods, such as waterflooding, recover substantially more of this oil, but still leave a large quantity of the oil still in place. This in place oil is difficult to remove due to the fact that the interfacial tension between the immiscible phases within the oil results in entrapping the oil in the pores of the formation material. In order to reduce the interfacial tension of the oil, certain fluid additives are usually introduced into the formation; for example, surface active agents are injected to reduce this interfacial tension. These fluids are usually followed by the injection of mobility control solutions having a viscosity sufficient to drive the now mobilized oil towards a producing well. To achieve this viscosity, the fluid bank containing this mobility control solution may include a polymer. In that this polymer is relatively expensive, efforts have been made to develop recovery methods which reduce the amount of polymer needed for the total flood project. One technique is to grade or decrease the concentration of the polymer within the mobility control fluid bank from a high concentration at the front thereof to a low concentration at the rear thereof. This method has had limited success in recovering additional oil; however, some serious drawbacks have developed through this use. The greatest drawback against utilizing this method of decreased grading is that in utilizing a relatively high concentration of the polymer a viscous polymer build-up forms within the injected fluid which plugs the formation, thereby substantially reducing the oil recovery by affecting the mobility control and the sweep efficiency of the injected fluids. One method of preventing the formation of these viscous zones is to reduce the overall concentration of the polymer within the injected fluid banks. By reducing the polymer concentration, the effective recovery yield from the project is obviously reduced. There is a need for a fluid flooding method which substantially reduces or eliminates the formation of these viscous zones, as well as reduces the amount of polymer needed for the project while maintaining the integrity of the mobility control.